Systems and methods for removing insulation disposed over conductors of implantable electric stimulation systems

ABSTRACT

A method for forming a lead or lead extension includes forming an arrangement of elongated conductors. Each of the conductors extends from a proximal end of the arrangement to a distal end of the arrangement. Each of the conductors includes a layer of insulation disposed over a conductive core. A conductor-separating element is disposed over either the proximal end or the distal end of the arrangement. The conductor-separating element includes a plurality of ablation windows defined in a body. An end of at least one of the elongated conductors is radially extended over a portion of the conductor-separating element such that a portion of the at least one elongated conductor extends across at least one of the ablation windows. Insulation from the portion of the at least one conductor extending across the ablation window is ablated to expose a portion of the conductive core of the elongated conductor.

CROSS-REFERENCE To RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 12/494,086 filed on Jun. 29, 2009, which is incorporated hereinby reference.

FIELD

The present invention is directed to the area of implantable electricalstimulation systems and methods of making and using the systems. Thepresent invention is also directed to systems and methods of removinginsulation encasing conductors disposed in implantable electricalstimulation systems.

BACKGROUND

Implantable electrical stimulation systems have proven therapeutic in avariety of diseases and disorders. For example, spinal cord stimulationsystems have been used as a therapeutic modality for the treatment ofchronic pain syndromes. Peripheral nerve stimulation has been used totreat chronic pain syndrome and incontinence, with a number of otherapplications under investigation. Functional electrical stimulationsystems have been applied to restore some functionality to paralyzedextremities in spinal cord injury patients.

Stimulators have been developed to provide therapy for a variety oftreatments. A stimulator can include a control module (with a pulsegenerator), one or more leads, and an array of stimulator electrodes oneach lead. The stimulator electrodes are in contact with or near thenerves, muscles, or other tissue to be stimulated. The pulse generatorin the control module generates electrical pulses that are delivered bythe electrodes to body tissue.

Conventional implanted electrical stimulation systems are oftenincompatible with magnetic resonance imaging (“MRI”) due to the largeradio frequency (“RF”) pulses used during MRI. The RF pulses cangenerate transient signals in the conductors and electrodes of animplanted lead. These signals can have deleterious effects including,for example, unwanted heating of the tissue causing tissue damage,induced currents in the lead, or premature failure of electroniccomponents.

BRIEF SUMMARY

In one embodiment, a method for forming a lead or lead extensionincludes forming an arrangement of a plurality of elongated conductors.Each conductor extends from a proximal end of the arrangement to adistal end of the arrangement. Each of the plurality of conductorsincludes a layer of insulation disposed over a conductive core. Aconductor-separating element is disposed over one of the proximal end orthe distal end of the arrangement. The conductor-separating elementincludes a plurality of ablation windows defined in a body. An end of atleast one of the elongated conductors is radially extended over aportion of the conductor-separating element such that a portion of theat least one elongated conductor extends across at least one of theablation windows. Insulation from the portion of the at least oneconductor extending across the ablation window is ablated to expose aportion of the conductive core of the elongated conductor.

In another embodiment, a conductor-separating element includes a body, amounting aperture, and a plurality of retention devices. The bodydefines an outer rim and a plurality of ablation windows disposedcircumferentially around the body. The mounting aperture is positionedin a center of the body and is configured and arranged to receive aplurality of elongated conductors. The plurality of retention devicesare disposed around the outer rim of the body. Each retention device isconfigured and arranged to receive, and retain, an end of one of theconductors which passes through the center aperture and is bent over,and extended along, the body of the conductor-separating element. Theplurality of ablation windows are positioned such that, when the end ofone of the conductors is extended along the body of theconductor-separating element, the conductor has a portion that isexposed entirely around a transverse circumference of the conductorwithin the ablation window.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention aredescribed with reference to the following drawings. In the drawings,like reference numerals refer to like parts throughout the variousfigures unless otherwise specified.

For a better understanding of the present invention, reference will bemade to the following Detailed Description, which is to be read inassociation with the accompanying drawings, wherein:

FIG. 1 is a schematic view of one embodiment of an electricalstimulation system, according to the invention;

FIG. 2 is a schematic view of another embodiment of an electricalstimulation system, according to the invention;

FIG. 3A is a schematic view of one embodiment of a proximal portion of alead and a control module of an electrical stimulation system, accordingto the invention;

FIG. 3B is a schematic view of one embodiment of a proximal portion of alead and a lead extension of an electrical stimulation system, accordingto the invention;

FIG. 4 is a schematic side view of one embodiment of portions of aplurality of conductors disposed along a conductor placement sleeve, theconductors configured into units, according to the invention;

FIG. 5 is a schematic longitudinal cross-sectional view of oneembodiment of portions of a plurality of conductors disposed in anelongated member, according to the invention;

FIG. 6A is a schematic top view of one embodiment of a separatingelement for radially extending conductors of an elongated member,according to the invention;

FIG. 6B is a schematic top view of another embodiment of a separatingelement for radially extending conductors of an elongated member,according to the invention;

FIG. 6C is a schematic top view of yet another embodiment of aseparating element for radially extending conductors of an elongatedmember, the separating element including lumens defined in a body of theseparating element, according to the invention;

FIG. 7A is a schematic top view of one embodiment of the separatingelement of FIG. 6A coupled to one end of an elongated member havingconductors that are being radially extended by the separating element,according to the invention;

FIG. 7B is a schematic side view of one embodiment of the separatingelement of FIG. 6A coupled to one end of the elongated member of FIG. 7Ahaving conductors that are being radially extended by the separatingelement, according to the invention;

FIG. 7C is a schematic cross-sectional view of one embodiment of theseparating element of FIG. 6A coupled to one end of the elongated memberof FIG. 7A having conductors that are being radially extended by theseparating element to expose portions of the conductors for insulationremoval by ablators, according to the invention; and

FIG. 8 is a schematic overview of one embodiment of components of astimulation system, including an electronic subassembly disposed withina control module, according to the invention.

DETAILED DESCRIPTION

The present invention is directed to the area of implantable electricalstimulation systems and methods of making and using the systems. Thepresent invention is also directed to systems and methods of removinginsulation encasing conductors disposed in implantable electricalstimulation systems.

Suitable implantable electrical stimulation systems include, but are notlimited to, an electrode lead (“lead”) with one or more electrodesdisposed on a distal end of the lead and one or more terminals disposedon one or more proximal ends of the lead. Leads include, for example,percutaneous leads, paddle leads, and cuff leads. Examples of electricalstimulation systems with leads are found in, for example, U.S. Pat. Nos.6,181,969; 6,516,227; 6,609,029; 6,609,032; 6,741,892; 7,244,150;7,672,734; 7,761,165; 7,949,395; 7,974,706; and 8,175,710; U.S. PatentApplication Publications Nos. 2005/0165465 and 2007/0150036, all ofwhich are incorporated by reference.

FIG. 1 illustrates schematically one embodiment of an electricalstimulation system 100. The electrical stimulation system includes acontrol module (e.g., a stimulator or pulse generator) 102, a paddlebody 104, and at least one lead body 106 coupling the control module 102to the paddle body 104. The paddle body 104 and the one or more leadbodies 106 form a lead. The paddle body 104 typically includes an arrayof electrodes 134. The control module 102 typically includes anelectronic subassembly 110 and an optional, power source 120 disposed ina sealed housing 114. The control module 102 typically includes aconnector 144 (FIGS. 2 and 3A, see also 322 and 350 of FIG. 38) intowhich the proximal end of the one or more lead bodies 106 can be pluggedto make an electrical connection via conductive contacts on the controlmodule 102 and terminals (e.g., 310 in FIG. 3A and 336 of FIG. 3B) oneach of the one or more lead bodies 106. It will be understood that theelectrical stimulation system can include more, fewer, or differentcomponents and can have a variety of different configurations includingthose configurations disclosed in the electrical stimulation systemreferences cited herein. For example, instead of a paddle body 104, theelectrodes 134 can be disposed in an array at or near the distal end ofthe lead body 106 forming a percutaneous lead, as illustrated in FIG. 2.A percutaneous lead may be isodiametric along the length of the lead. Inaddition, one or more lead extensions 312 (see FIG. 38) can be disposedbetween the one or more lead bodies 106 and the control module 102 toextend the distance between the one or more lead bodies 106 and thecontrol module 102 of the embodiments shown in FIGS. 1 and 2.

The electrical stimulation system or components of the electricalstimulation system, including one or more of the lead bodies 106, thepaddle body 104, and the control module 102, are typically implantedinto the body of a patient. The electrical stimulation system can beused for a variety of applications including, but not limited to, brainstimulation, neural stimulation, spinal cord stimulation, musclestimulation, and the like.

The electrodes 134 can be formed using any conductive, biocompatiblematerial. Examples of suitable materials include metals, alloys,conductive polymers, conductive carbon, and the like, as well ascombinations thereof. The number of electrodes 134 in the array ofelectrodes 134 may vary. For example, there can be two, four, six,eight, ten, twelve, fourteen, sixteen, or more electrodes 134. As willbe recognized, other numbers of electrodes 134 may also be used.

The electrodes of the paddle body 104 or one or more lead bodies 106 aretypically disposed in, or separated by, a non-conductive, biocompatiblematerial including, for example, silicone, polyurethane,polyetheretherketone (“PEEK”), epoxy, and the like or combinationsthereof. The paddle body 104 and one or more lead bodies 106 may beformed in the desired shape by any process including, for example,molding (including injection molding), casting, and the like. Electrodesand connecting wires can be disposed onto or within a paddle body eitherprior to or subsequent to a molding or casting process. Thenon-conductive material typically extends from the distal end of thelead to the proximal end of each of the one or more lead bodies 106. Thenon-conductive, biocompatible material of the paddle body 104 and theone or more lead bodies 106 may be the same or different. The paddlebody 104 and the one or more lead bodies 106 may be a unitary structureor can be formed as two separate structures that are permanently ordetachably coupled together.

Terminals (e.g., 310 in FIG. 3A and 336 of FIG. 38) are typicallydisposed at the proximal end of the one or more lead bodies 106 forconnection to corresponding conductive contacts (e.g., 314 in FIG. 3Aand 340 of FIG. 3B) in connectors (e.g., 144 in FIGS. 1-3A and 322 and350 of FIG. 3B) disposed on, for example, the control module 102 or toother devices, such as conductive contacts on a lead extension, anoperating room cable, or an adaptor). Conductive wires (“conductors”)(not shown) extend from the terminals (e.g., 310 in FIG. 3A and 336 ofFIG. 3B) to the electrodes 134. Typically, one or more electrodes 134are electrically coupled to a terminal (e.g., 310 in FIG. 3A and 336 ofFIG. 3B). In some embodiments, each terminal (e.g., 310 in FIG. 3A and336 of FIG. 3B) is only connected to one electrode 134. The conductivewires may be embedded in the non-conductive material of the lead or canbe disposed in one or more lumens (riot shown) extending along the lead.In some embodiments, there is an individual lumen for each conductivewire. In other embodiments, two or more conductive wires may extendthrough a lumen. There may also be one or more lumens (not shown) thatopen at, or near, the proximal end of the lead, for example, forinserting a stylet rod to facilitate placement of the lead within a bodyof a patient. Additionally, there may also be one or more lumens (notshown) that open at, or near, the distal end of the lead, for example,for infusion of drugs or medication into the site of implantation of thepaddle body 104. In at least one embodiment, the one or more lumens maybe flushed continually, or on a regular basis, with saline, epiduralfluid, or the like. In at least some embodiments, the one or more lumenscan be permanently or removably sealable at the distal end.

In at least some embodiments, leads are coupled to connectors disposedon control modules. In FIG. 3A, a lead 308 is shown configured andarranged for insertion to the control module 102. The connector 144includes a connector housing 302. The connector housing 302 defines atleast one port 304 into which a proximal end 306 of a lead 308 withterminals 310 can be inserted, as shown by directional arrow 312. Theconnector housing 302 also includes a plurality of conductive contacts314 for each port 304. When the lead 308 is inserted into the port 304,the conductive contacts 344 can be aligned with the terminals 310 on thelead 308 to electrically couple the control module 102 to the electrodes(134 of FIG. 1) disposed at a distal end of the lead 308. Examples ofconnectors in control modules are found in, for example, U.S. Pat. Nos.7,244,150 and 8,224,450, which are incorporated by reference.

In FIG. 3B, a connector 322 is disposed on a lead extension 324. Theconnector 322 is shown disposed at a distal end 326 of the leadextension 324. The connector 322 includes a connector housing 328. Theconnector housing 328 defines at least one port 330 into which aproximal end 332 of a lead 334 with terminals 336 can be inserted, asshown by directional arrow 338. The connector housing 328 also includesa plurality of conductive contacts 340. When the lead 334 is insertedinto the port 330, the conductive contacts 340 disposed in the connectorhousing 328 can be aligned with the terminals 336 on the lead 334 toelectrically couple the lead extension 324 to the electrodes (134 ofFIG. 1) disposed at a distal end (not shown) of the lead 334.

In at least some embodiments, the proximal end of a lead extension issimilarly configured and arranged as a proximal end of a lead. The leadextension 324 may include a plurality of conductive wires (not shown)that electrically couple the conductive contacts 340 to a proximal end348 of the lead extension 324 that is opposite to the distal end 326. Inat least some embodiments, the conductive wires disposed in the leadextension 324 can be electrically coupled to a plurality of terminals(not shown) disposed on the proximal end 348 of the lead extension 324.In at least some embodiments, the proximal end 348 of the lead extension324 is configured and arranged for insertion into a connector disposedin another lead extension. In other embodiments, the proximal end 348 ofthe lead extension 324 is configured and arranged for insertion into aconnector disposed in a control module. As an example, in FIG. 3B theproximal end 348 of the lead extension 324 is inserted into a connector350 disposed in a control module 352.

One or more of the conductors connecting at least one terminal to anelectrode (or other conductive contact) can be arranged in a conductorpath to eliminate or reduce the effect of RE irradiation, such as thatgenerated during magnetic resonance imaging (“MRI”). The conductor pathincludes a plurality of units arranged in series. In some embodiments,the units are disposed along a single continuous conductor. In otherembodiments, the units are separate conductive elements electricallycoupled together.

Each unit includes at least three conductor segments that at leastpartially overlap one another to form a multi-coil region. First, eachunit includes a first conductor segment that extends in a firstdirection along a longitudinal length of an elongated member (e.g., alead or lead extension) from a beginning point to a first position.Second, each unit includes a second conductor segment that extends fromthe first position back towards (and possibly past) the beginning pointto a second position. Third, each unit includes a third conductorsegment that extends in the first direction from the second position toan endpoint. In at least some embodiments, the first position is betweenthe second position and the endpoint. In at least some embodiments, thesecond position is between the beginning point and the first position.In at least some embodiments, the unit may include a single-coil regionflanking at least one end of the multi-coil region.

The units may be electrically continuous such that the endpoint of afirst unit is the beginning point of the next consecutive unit. At leastone of the beginning points may be a terminal or an electrode (or otherconductive contact). Likewise, at least one of the endpoints may be aterminal or an electrode (or other conductive contact). In preferredembodiments, the conductor segments are each coiled. In at least someembodiments, the conductor segments are coiled around a conductorplacement sleeve. In at least sonic embodiments, the conductor placementsleeve defines a lumen that optionally is configured and arranged toreceive a stiffening member (e.g., a stylet, or the like).

In at least some embodiments, at least one of the first, second, orthird conductor segments is substantially straight. In at least someembodiments, the first and third conductor segments are substantiallystraight and the second conductor segment is coiled. In at least someother embodiments, all three conductor segments are substantiallystraight. It will be understood that the term “substantially straightconductor segment” means that the conductor segment is not coiled. A“substantially straight conductor segment” may be curved, particularlywhen the lead itself is curved (see, for example, FIG. 1).

In at least some embodiments, the conductor segments are all formed fromthe same length of conductive material (e.g., wire or the like). Theconductors may have a single filament or be multi-filar. In preferredembodiments, the conductors are multi-filar. In at least someembodiments, two or more of the conductor segments can be individualpieces of conductive material that are electrically coupled (e.g.,soldered or welded) together. In at least sonic embodiments, a layer ofinsulation (“conductor insulation”) is disposed over each of theconductor segments.

In at least some embodiments, the length of conductor used in the secondconductor segment is at least 1.5, 1.75, 1.9, 2, 2.1, 2.25, or 2.5 timesthe length of either the first conductor segment or the third conductorsegment. It will be recognized, however, that this ratio ofconductor-segment lengths may vary among embodiments, particularly ifthe thickness of the conductor or thickness of the layer of conductorinsulation is different for the different segments.

FIG. 4 schematically illustrates one embodiment of a plurality ofconductors 402. The conductors 402 are configured into a plurality ofunits, such as unit 404. Each unit includes a first conductor segment404 a, a second conductor segment 404 b, and a third conductor segment404 c. In at least some embodiments, conductor insulation is disposedover the conductors 402 to electrically isolate each of the conductors402 from one another.

Many different numbers of units may be disposed along longitudinallengths of the conductors 402 including, for example, two, three, four,five, six, seven, eight, nine, ten, twelve, fifteen, twenty,twenty-five, thirty, forty, fifty, or more units. It will be understoodthat many other numbers of units may be employed as well. When aplurality of units are coupled together in series along a longitudinallength of one or more conductors, the plurality of units form arepeating series of single-coil regions, such as the single-coil regions406, separated from one another by a multi-coil region, such as themulti-coil region 408.

In at least some embodiments, the conductors 402 are disposed along aconductor placement sleeve 410. The conductor placement sleeve 410 canbe fanned from any suitable biocompatible material including, forexample, one or more polymers. In at least some embodiments, conductorinsulation is disposed over the conductors 402 to encapsulate theconductors 402 and electrically isolate the conductors 402 from oneanother.

In at least some embodiments, one or more conductors having one or moreunits may be disposed in an elongated member (e.g., a lead or leadextension). In at least some embodiments, the ends of the conductors 402can be coupled to terminals, electrodes, or conductive contacts. Inpreferred embodiments, each of the conductors in an elongated member areconfigured into units. In at least some embodiments, only a subset ofthe conductors disposed in an elongated member include one or moreunits, the remaining conductors having a different arrangement (forexample, a single conductor segment between the terminal(s) andelectrode(s)/conductive contact(s)).

Conductors, such as the conductors 402, may be disposed in a lumen of anelongated member (e.g., a lead, lead extension, or the like). FIG. 5 isa schematic longitudinal cross-sectional view of one embodiment ofportions of a plurality of conductors 502 disposed in an elongatedmember 504. The illustrated portions of the conductors 502 includes unit506, shown between two vertical dotted lines. Unit 506 includes a firstconductor segment 506 a, a second conductor segment 506 b, and a thirdconductor segment 506 c. In at least some embodiments, the conductors502 are disposed over a conductor placement sleeve 508. In at least someembodiments, the conductor placement sleeve 508 defines a lumen 510. Theelongated member 504 includes a body 512 and a lumen 514 into which theconductors 502 are disposed.

As mentioned above, one or more conductors typically extend along atleast a portion of the longitudinal length of the elongated member,electrically coupling at least one terminal to an electrode (or otherconductive contact). Typically, the conductors are individually encasedin a layer of insulation. The number of conductors disposed in theelongated member may vary. Additionally, the conductors in the elongatedmember may be disposed in many different possible configurations (e.g.,arranged into units, coiled into a helical configuration, disposed in amulti-lumen device, disposed over a sleeve, disposed over a mandrel, orthe like).

It may be the case that the conductors are pre-fabricated into a body ofthe elongated member such that each of the conductors is individuallyencased in the layer of insulation. During formation of the elongatedmember, the conductors are disposed in the elongated member such thatthe proximal ends of the conductors extend outward from a proximal endof the outer layer of the elongated member and the distal ends of theconductors extend outward from a distal end of the outer layer of theelongated member. The terminals are then electrically coupled to theproximal ends of the conductors and the electrodes (or conductivecontacts) are electrically coupled to the distal ends of the conductors.

The layer of insulation encasing the conductors is removed from aportion of each of the conductors extending from the proximal end of theouter layer of the elongated member so that the proximal ends of theconductors can be coupled to the terminals. Likewise, the layer ofinsulation encasing the conductors is removed from a portion of each ofthe conductors extending from the distal end of the outer layer of theelongated member so that the distal ends of the conductors can becoupled to the electrodes (or other conductive contacts). It ispreferable to remove as little insulation as is necessary to makeelectrical contact with the terminal or electrode (or other conductivecontact) in order to reduce the chance of electrical shorts. Insulationremoval may be difficult when access to the ends of the conductors is atleast partially obstructed by other conductors, such as when theconductors are disposed in elaborate configurations or when theconductors are tightly packed in the elongated member.

One technique for insulation removal involves ablating (e,g, laserablating or the like) the insulation. In some cases, insulation isremoved after the conductors are disposed in the elongated member. Onedifficulty with removing insulation after the conductors are disposed inthe elongated member is that ablation techniques typically requireline-of-sight access to a complete circumference of the portion of theinsulation to be removed, thereby exposing the entire transversecircumference of the conductor. Not all conductor configurations (e.g.,coiled conductors, conductors formed into units, or the like) allow forexposure of the entire transverse circumference of the portion of theconductor where insulation is to be removed.

In some cases, the conductors may be pre-ablated prior to being disposedin the elongated member, thereby ensuring line-of-sight access to acomplete circumference of the portion of the insulation to be removed.Aligning pre-ablated conductors, however, after the conductors have beendisposed in the elongated member may require application of force toindividual conductors. It may also be difficult to align the conductorsif the ablation sites do not meet strict tolerances in positioning.

Additionally, some conductor configurations (e.g., conductors formedinto units) are not conducive to pre-ablation. For example, when forminga coiled configuration of conductors it can sometimes be difficult toaccurately position an ablated section within required tolerances.Typically, coiled configurations are formed with conductors beingremoved from spools and fed into a coiling machine. Ablation would needto be performed in the middle of this removal operation, thereby addingan additional layer of complexity.

In at least some embodiments, insulation may be removed from conductorsafter the conductors have been configured into a desired arrangement anddisposed in the elongated member using a conductor-separating element(“separating element”). In at least some embodiments, the separatingelement is removably disposed over the outer layer of the elongatedmember and may be used to radially extend one or more conductorsextending from the ends of the outer layer of the elongated member. Theradially extended conductors may be retained in a radially-extendedposition such that portions of the conductors may be separated front oneanother and adequately exposed for ablative insulation removal. It willbe understood that a separating element may be used with conductorsdisposed in the elongated member in many different configurations (e.g.,arranged into units, coiled into a helical configuration, disposed in amulti-lumen device, disposed over a sleeve, disposed over a mandrel, orthe like).

FIG. 6A is a schematic top view of one embodiment of a separatingelement 602. The separating element 602 includes a body 604, a coupler606, and an outer rim 608. A plurality of ablation windows, such asablation window 610, are also defined in the body 604.

In at least sonic embodiments, the coupler 606 defines a mountingaperture configured and arranged to receive the elongated member. In atleast some embodiments, the coupler 606 is configured and arranged to bepositioned at either end of the outer layer of the elongated member. Thecoupler 606 may be positioned anywhere on the body 604. In preferredembodiments, the coupler 606 is located in proximity to the center ofthe body 604. In at least some embodiments, the coupler 606 includes aretention device (not shown) to retain the separating element 602 inposition, when the separating element 602 is disposed over an elongatedmember.

The separating element 602 may have any transverse cross-sectional shapeincluding, for example, triangular, square, pentagonal, hexagonal,heptagonal, octagonal, nonagonal, decagonal, circular, oval, or thelike. In at least some embodiments, the separating element 602 has anon-geometric transverse cross-sectional shape. In a preferredembodiment, the separating element 602 has a circular transversecross-sectional shape. In at least some embodiments, the separatingelement 602 is cone-shaped. The separating element 602 may be fabricatedfrom any material that is rigid enough to retain conductors in aradially-extended position while insulation is removed from theconductors.

in at least some embodiments, retention devices (e.,g., a clamp or thelike), such as retention device 612, are positioned along the outer rim608. The retention devices 612 may be used to retain the conductors inradially-extended positions when the conductors are extended along thelumens, in at least some embodiments, the body 604 may include one ormore guide features (e.g., channels, clips, or the like) to guide aconductor across one or more of the ablation windows 610 to one of theretention devices 612.

In at least some embodiments, the ablation windows 610 extend throughthe body 604. In at least some embodiments, the ablation windows 610 arepositioned such that, when one of the conductors is disposed along theseparating element, the conductor extends across the ablation window,thereby providing line-of-sight access entirely around a transversecircumference of the portion of the conductor extending across theablation window. In at least some embodiments, the ablation windows 610are positioned such that, when one of the conductors is disposed in theseparating element, the conductor extends across the ablation window,thereby providing adequate space to ablate (e.g., laser ablate or thelike) a portion of the insulation encasing the conductor entirely aroundthe transverse circumference of the conductor. In at least someembodiments, the ablation windows 610 are positioned such that, when oneof the conductors is disposed in the separating element, the conductorextends across the ablation window, thereby providing enough space toelectrically couple (e.g., laser weld, resistance weld, cut, swage,crimp, solder, or the like) the conductor to a terminal or electrode (orconductive contact) once an adequately-sized portion of the insulationhas been removed.

The ablation windows 610 may be defined in the body 604 at any radialdistance from the center of the body 604. The distance between thecoupler 606 and a given ablation window 610 approximates the distancefrom the end of the outer layer of the elongated member that theinsulation of the corresponding conductor is removed. In at least someembodiments, the ablation windows 610 are radially staggered so that,when the insulation is removed from the conductors, the exposed portionsof the conductors are staggered so that terminals or electrodes (orconductive contacts) may be electrically coupled to the exposed portionsof the conductors in a staggered arrangement.

The ablation windows 610 may have any transverse cross-sectional shapeincluding, for example, triangular, square, pentagonal, hexagonal,heptagonal, octagonal, nonagonal, decagonal, circular, oval, or thelike. In at least some embodiments, the ablation windows 610 havenon-geometric transverse cross-sectional shapes.

It will be understood that the separating element may include manydifferent ablation-window configurations. For example, each of theablation windows may be defined at the same radial distance from thecenter of the body 604. In at least some embodiments, the radialpositioning of one or more of the ablation windows may be adjustable sothat the distance between the end of the elongated member and theremoved portion of the insulation may be controlled.

It will be understood that the separating element may be formed in manydifferent ways. For example, the body may include less material or theablation windows may be larger-sized in relation to the size of thebody, as compared to the ablation windows 610 and body 604 of FIG. 6A.FIG. 6B illustrates another embodiment of a separating element 650having a body 652 that includes a plurality of spokes separating acoupler 654 from an outer rim 656. Ablation windows, such as ablationwindow 658 are defined by the coupler 654, the outer rim 656, and twoadjacent spokes of the body 652. Thus, roost of the longitudinal lengthof the conductors disposed in the separating element 650 may beaccessible between the coupler 654 and the outer rim 656. In at leastsome embodiments, the separating element 650 includes retention devices,such as retention device 660, to retain the conductors in aradially-extended position when conductors are disposed in theseparating element 650. In at least some embodiments, the outer rim 656defines lumens, such as lumen 662, through which at least a portion ofthe conductors may extend when the conductors are disposed in theseparating clement 650. In at least some embodiments, the outer rim 656does not include lumens.

It will be understood that the body 652 may include spokes that arenon-isodiametric. For example, in at least some embodiments, the body652 includes spokes that are triangular-shaped, thereby giving the body652 a dartboard-like appearance.

The ablation windows 610 and 658 allow the conductors to be held inposition such that portions of the insulation encasing a given conductormay be removed in relation to the other conductors. It may be anadvantage to be able to remove insulation from one end of each of theconductors relative to one another to ensure proper placement of theinsulation removal without having to push or pull a given conductor inor out of the elongated member to align removed insulation with theremoved insulation of other conductors disposed in the elongated member.

Separating elements may be formed to accommodate many different numbersof conductors including, for example, one, two, three, four, five, six,seven, eight, nine, ten, twelve, sixteen, twenty, twenty-four, thirty,thirty-two, fifty, sixty-four or more conductors. It will be understoodthat separating elements may be formed to accommodate many other numbersof conductors, as well.

In at least some embodiments, the separating element may define one ormore lumens through which one or more conductors may extend when aconductor is disposed on the separating element. FIG. 6C is a schematictop view of yet another embodiment of a separating element 680 having abody 682 that defines lumens, such as lumen 684, extending radiallyoutward from a location in proximity to a center of the body 682. In atleast some embodiments, the lumens 684 are configured and arranged toalign with ablation windows, such as ablation window 686, defined in thebody 682. In at least some embodiments, the lumens 684 are configuredand arranged to align with retention devices, such as retention device688, defined in the body 682.

In at least some embodiments, the lumens 684 are configured and arrangedto receive the ends of the conductors disposed on the separatingelement. The lumens 684 are configured and arranged to separate the endsof each of the conductors from one another. In at least someembodiments, the lumens 684 extend from an insertion aperture, such asinsertion aperture 690. The insertion aperture 690 may be anywhere alonga length of the lumens 684. For example, in some embodiments theinsertion apertures 690 are positioned in a center of the body 682. Inother embodiments the insertion apertures 690 are positioned along thelength of the lumens 684, either medial or lateral to the ablationwindows 686.

In at least some embodiments, terminals or electrodes (or conductivecontacts) can be electrically coupled to the conductors while theconductors are disposed in the separating element. Accordingly, it maybe an advantage to have the insertion apertures 688 positioned lateralto the ablation windows 686 so that the conductors andelectrically-coupled terminals or electrodes (or conductive contacts)can be removed from the separating element without needing to withdrawthe electrically-coupled terminals or the electrodes (or conductivecontacts) through the lumens.

FIGS. 7A-7C illustrate conductors of an elongated member disposed in theseparating element 680. Accordingly, the conductors are shown disposedin lumens defined in the body. It will be understood that conductors maysimilarly be disposed along the separating elements 602 and 650. Theseparating element 602, however, does not include lumens. Thus,conductors are disposed along a surface of the body 604 instead of beingdisposed within lumens.

FIG. 7A is a schematic top view of one embodiment of the separatingelement 680 coupled to one end of an outer layer 702 of an elongatedmember 704. A plurality of conductors, such as conductor 706, aredisposed in the elongated member 704. The ends of the conductors 706 areinserted into lumens of the separating element 680 and radially extendedoutward front the outer layer 702 of the elongated member 704.

As discussed above, the separating element 680 may be used to spread andexpose conductors 706 extending from one end of the outer layer 702 ofthe elongated member 704 to facilitate removal of the layer ofinsulation encasing each of the conductors 706. The conductors 706 maybe disposed in the elongated member 704 in many different configurations(e.g., arranged into units, coiled into a helical configuration,disposed in a multi-lumen device, disposed over a sleeve, disposed overa mandrel, or the like). In FIG. 7A, the portions of the conductors 706disposed in the elongated member 704 are shown wrapped around a sleeveor a mandrel 708.

FIG. 7B is a schematic side view of one embodiment of the separatingelement 680 disposed over one end of the outer layer 702 of theelongated member 704. The plurality of conductors 706 are disposed inthe elongated member 704. Each of the conductors 706 extends through adifferent one of the retention devices 688 of the separating element680, thereby radially extending the conductors 706 from the elongatedmember 704.

FIG. 7C is a schematic cross-sectional view of one embodiment of theseparating element 680 disposed over one end of the outer layer 702 ofthe elongated member 704. The conductors 706 are extending radiallyoutward from the elongated member 704 and are separated from oneanother. One or more ablators 710 are positioned in proximity toablation windows 686 defined in the separating element 680. In preferredembodiments and as shown in FIG. 7C, the conductors 706 extend acrossthe ablation windows 686 such that the complete circumference of theportion of the insulation to be removed from the conductors 706 isaccessible by the ablators 710.

In at least some embodiments, the elongated member may be formed bydisposing conductors into the elongated member such that the proximalends of the conductors extend outward from a proximal end of the outerlayer of the elongated member and the distal ends of the conductorsextend outward front a distal end of the outer layer. The coupler of theseparating element is disposed over the proximal end of the outer layerof the elongated member. The conductors are disposed in the separatingelement such that the conductors extend radially-outward from theelongated member, extending across ablation windows. In at least someembodiments, the ends of the conductors are held in position byretention devices disposed in proximity to the outer rim of theseparating device. Portion of the layers of insulation encasing theconductors are removed in the regions of the conductors spanning theablation windows of the separating element. In at least someembodiments, when one end of the conductors are disposed in theseparating element and retained by one of the retention devices, tensionmay be applied to the conductors along a portion of the conductors notdisposed on the separating element to pull the conductors tight acrossthe ablation windows, thereby reducing sag across the ablation windows.

In at least some embodiments, the separating element is then removedfrom the proximal end of the elongated member and further processing ofthe conductors may be performed. For example, terminals are electricallycoupled (e.g., laser welded, resistance welded, cut, swaged, crimped,soldered, or the like) to the portions of the conductors exposed by theremoved insulation. In at least some other embodiments, the terminalsare electrically coupled to the conductors while the conductors arestill disposed in the separating element, and the conductors aresubsequently removed from the proximal end of the elongated member.

Once the separating element is removed from the proximal end of theelongated member, the separating element may be disposed on the distalend of the elongated member and the same process is performed with thedistal end of the conductors. Electrodes (or conductive contacts),however, are electrically coupled to the distal end of the conductorsinstead of terminals.

In at least some embodiments, the layers of insulation are removed fromthe conductors by laser ablation. In at least some embodiments, theseparating element (with conductors disposed in the separating element)is configured and arranged for placement in a laser ablation system. Inat least some embodiments, the laser ablation system may be configuredand arranged to automatically remove insulation from desired conductorsat desired locations.

FIG. 8 is a schematic overview of one embodiment of components of anelectrical stimulation system 800 including an electronic subassembly810 disposed within a control module. It will be understood that theelectrical stimulation system can include more, fewer, or differentcomponents and can have a variety of different configurations includingthose configurations disclosed in the stimulator references citedherein.

Some of the components (for example, power source 812, antenna 818,receiver 802, and processor 804) of the electrical stimulation systemcan be positioned on one or more circuit boards or similar carrierswithin a sealed housing of an implantable pulse generator, if desired.Any power source 812 can be used including, for example, a battery suchas a primary battery or a rechargeable battery. Examples of other powersources include super capacitors, nuclear or atomic batteries,mechanical resonators, infrared collectors, thermally-powered energysources, flexural powered energy sources, bioenergy power sources, fuelcells, bioelectrie cells, osmotic pressure pumps, and the like includingthe power sources described in U.S. Pat. No. 7,437,193, incorporatedherein by reference.

As another alternative, power can be supplied by an external powersource through inductive coupling via the optional antenna 818 or asecondary antenna. The external power source can be in a device that ismounted on the skin of the user or in a unit that is provided near theuser on a permanent or periodic basis.

If the power source 812 is a rechargeable battery, the battery may berecharged using the optional antenna 818, if desired. Power can beprovided to the battery for recharging by inductively coupling thebattery through the antenna to a recharging unit 816 external to theuser. Examples of such arrangements can be found in the referencesidentified above.

In one embodiment, electrical current is emitted by the electrodes 134on the paddle or lead body to stimulate nerve fibers, muscle fibers, orother body tissues near the electrical, stimulation system. A processor804 is generally included to control the timing and electricalcharacteristics of the electrical stimulation system. For example, theprocessor 804 can, if desired, control one or more of the timing,frequency, strength, duration, and waveform of the pulses. In addition,the processor 804 can select which electrodes can be used to providestimulation, if desired. In some embodiments, the processor 804 mayselect which electrode(s) are cathodes and which electrode(s) areanodes. In some embodiments, the processor 804 may be used to identifywhich electrodes provide the most useful stimulation of the desiredtissue.

Any processor can be used and can be as simple as an electronic devicethat, for example, produces pulses at a regular interval or theprocessor can be capable of receiving and interpreting instructions froman external programming unit 808 that, for example, allows modificationof pulse characteristics. In the illustrated embodiment, the processor804 is coupled to a receiver 802 which, in turn, is coupled to theoptional antenna 818. This allows the processor 804 to receiveinstructions from an external source to, for example, direct the pulsecharacteristics and the selection of electrodes, if desired.

In one embodiment, the antenna 818 is capable of receiving signals(e.g., RF signals) from an external telemetry unit 806 which isprogrammed, by a programming unit 808. The programming unit 808 can beexternal to, or part of the telemetry unit 806. The telemetry unit 806can be a device that is worn on the skin of the user or can he carriedby the user and can have a form similar to a pager, cellular phone, orremote control, if desired. As another alternative, the telemetry unit806 may not be worn or carried by the user but may only be available ata home station or at a clinician's office. The programming unit 808 canbe any unit that can provide information to the telemetry unit 806 fortransmission to the electrical stimulation system 800. The programmingunit 808 can be part of the telemetry unit 806 or can provide signals orinformation to the telemetry unit 806 via a wireless or wiredconnection. One example of a suitable programming unit is a computeroperated by the user or clinician to send signals to the telemetry unit806.

The signals sent to the processor 804 via the antenna 818 and receiver802 can be used to modify or otherwise direct the operation of theelectrical stimulation system. For example, the signals may be used tomodify the pulses of the electrical stimulation system such as modifyingone or more of pulse duration, pulse frequency, pulse waveform, andpulse strength. The signals may also direct the electrical stimulationsystem 800 to cease operation, to start operation, to start charging thebattery, or to stop charging the battery. In other embodiments, thestimulation system does not include an antenna 818 or receiver 802 andthe processor 804 operates as programmed.

Optionally, the electrical stimulation system 800 may include atransmitter (not shown) coupled to the processor 804 and the antenna 818for transmitting signals back to the telemetry unit 806 or another unitcapable of receiving the signals. For example, the electricalstimulation system 800 may transmit signals indicating whether theelectrical stimulation system 800 is operating properly or not orindicating when the battery needs to be charged or the level of chargeremaining in the battery. The processor 804 may also be capable oftransmitting information about the pulse characteristics so that a useror clinician can determine or verify the characteristics.

The above specification, examples and data provide a description of themanufacture and use of the composition of the invention. Since manyembodiments of the invention can be made without departing from thespirit and scope of the invention, the invention also resides in theclaims hereinafter appended.

What is claimed as new and desired to be protected by Letters Patent ofthe United States is:
 1. A kit for making a lead or lead extension, thekit comprising an elongated bundle of conductor wires, each conductorwire comprising a conductive core and a layer of insulation disposedover the conductive core; a wire-separating element comprising a solidbody defining a center, an outer rim, and a plurality of windowsdisposed circumferentially around the body, a mounting apertureconfigured and arranged to receive the bundle of conductor wires,wherein the mounting aperture is positioned at the center of the body, aplurality of retention devices disposed around the outer rim of thebody, each retention device configured and arranged to receive, andretain, an end of one of the conductor wires which passes through thecenter aperture and is bent over, and extended along, the body of theconductor-separating element, wherein, the plurality of windows arepositioned such that, when a one of the conductors is extended along thebody of the conductor-separating element and received in a one of theretention devices, the one of the conductors has a portion that isentirely exposed through a one of the windows; and a laser ablationsystem configured and arranged to ablate a portion of the layer ofinsulation of each of the conductor wires through the windows.
 2. Thekit of claim 1, wherein the plurality of windows are radially staggeredso that each window is a different distance from the center of the body.3. The kit of claim 2, wherein the plurality of windows are arranged ina spiral.
 4. The kit of claim 1, wherein the wire-separating elementcomprises a plurality of spokes coupling the outer rim to the mountingaperture.
 5. The kit of claim 4, wherein each of the windows is definedby the outer rim, the mounting aperture, and two adjacent spokes of theplurality of spokes.
 6. The kit of claim 1, wherein the wire-separatingelement comprises a plurality of lumens radiating out from the mountingaperture and configured and arranged to receive individual ones of theconductor wires.
 7. The kit of claim 1, wherein the bundle of conductorwires comprises at least eight conductor wires.
 8. The kit of claim 7,wherein the wire-separating element is configured and arranged tosimultaneously and individually receive each of the conductor wires indifferent retention devices of the plurality of retention devices. 9.The kit of claim 1, further comprising a plurality of electrodesconfigured and arranged for electrically coupling to the conductor wiresafter ablation of the layer of insulation, wherein the windows are sizedto permit coupling of the electrodes to the conductor wires while theconductor wires are exposed through the windows.
 10. The kit of claim 1,further comprising a plurality of terminals configured and arranged forelectrically coupling to the conductor wires after ablation of the layerof insulation, wherein the windows are sized to permit coupling of theterminals to the conductor wires while the conductor wires are exposedthrough the windows.
 11. The kit of claim 1, further comprising aplurality of conductive contacts configured and arranged forelectrically coupling to the conductor wires after ablation of the layerof insulation, wherein the windows are sized to permit coupling of theconductive contacts to the conductor wires while the conductor wires areexposed through the windows.
 12. The kit of claim 1, wherein each of theconductor wires is multi-filar.
 13. The kit of claim 1, wherein each ofthe conductor wires is a single filament.
 14. A wire-separating element,comprising: a solid body defining a center, an outer rim, and aplurality of windows disposed circumferentially around the body; amounting aperture configured and arranged to receive a bundle ofconductor wires, wherein the mounting aperture is positioned at thecenter of the body; and a plurality of retention devices disposed aroundthe outer rim of the body, each retention device configured and arrangedto receive, and retain, an end of one of the conductor wires whichpasses through the center aperture and is bent over, and extended along,the body of the conductor-separating element; wherein the plurality ofwindows are positioned such that, when a one of the conductors isextended along the body of the conductor-separating element and receivedin a one of the retention devices, the one of the conductor wires has aportion that is entirely exposed through a one of the windows to allowablation of a layer of insulation on the conductor wire.
 15. Thewire-separating element of claim 14, wherein the plurality of windowsare radially staggered so that each window is a different distance fromthe center of the body.
 16. The wire-separating element of claim 15,wherein the plurality of windows are arranged in a spiral.
 17. Thewire-separating element of claim 14, further comprising a plurality ofspokes coupling the outer rim to the mounting aperture.
 18. Thewire-separating element of claim 17, wherein each of the windows isdefined by the outer rim, the mounting aperture, and two adjacent spokesof the plurality of spokes.
 19. The wire-separating element of claim 14,further comprising a plurality of lumens radiating out from the mountingaperture and configured and arranged to receive individual ones of theconductor wires.
 20. The wire-separating element of claim 14, whereinthe wire-separating element is configured and arranged to simultaneouslyand individually receive at least eight conductor wires in differentretention devices of the plurality of retention devices.